Polishing machine



June 12, 1934. J. P. BUCKLEY 1,962,135

POLISHING MACHINE Filed Feb. 19, 1950 2 Sheets-Sheet 1 June 12, 1934. J, p BUCKLEY 1,962,135

POLISHING MACHINE Filed Feb. 19, 1930 2 Sheets-Sheet 2 FIG. 2.

Patented June 12, 1934 PATENT OFFICE POLISHING MACHINE John P. Buckley,

Washington, D. 0.

Application February 19, 1930; Serial No. 429,776

7 Claims.

This invention relates to grinding and polishing and more particularly to a machine by means of which a specimen of glass, metal or other substances may be polished prior to inspection under a microscope for detection of flaws or imperfections in the specimen.

At the present time it is customary to polish a specimen before inspecting it under a microscope or making a microscopic photograph there- I of for future study but it has been found that when a specimen is polished according to methods now in use minute scratches are formed which are liable to be mistaken for imperfections in the specimen and it also often happens that margins of a flaw will become blurred due to scratching.

Therefore, one object of this invention is to provide a machine by means of which a specimen may have a surface very highly polished Without scratches being formed thereon which are likely to make a difficult to clearly distinguish flaws and further cause the margins of flaws to be very sharply defined when the specimen is viewed through a microscope or a microscopic photograph thereof studied.

Another object of the'invention is to so construct the improved polishing machine that a rotating polishing surface is provided against which the specimen to be polished is applied and to so mount the specimen that it will be moved radially across the polishing surface and at the same time rotated at a slower rate of speed than the speed at which the polishing surface moves thereby causing a very high polish to he formed upon the specimen due to the fact that scratches are not formed in a given path across the specimen.

Another object of the invention is to provide improved means forholding a specimen to be polished and also provide means for yieldably applying pressure to force the specimen downwardly against the polishing surface.

Another object of the invention is to provide a machine of this character so constructed that Figure 3 is an enlarged view showing a portion of the machine in elevation,

Figure 4 is a top plan view of a portion of Figure 4 with portions omitted for sake of clearness, and

Figure 5 is a perspective view of the article holder and portions of the pressure applying means.

The frame of this improved polishing machine is similar in construction to a table and has a top 1 supported upon a suitable number of legs 2 which are braced by stringers 3 and beneath the top is mounted a shelf or platform 4. A drive shaft 5 is rotatably mounted in bearings 6 secured upon the shelf and at one end is secured to the shaft of a motor 7. Fitted upon the shaft 5 is a friction gear or disk 8 having a hub extension 9 terminating in a clutch for engagement by a companion clutch sleeve 10 keyed to the shaft and this clutch is engaged by a fork 11 which is pivotally mounted, as shown at 12, and yieldably held in position to retain the clutch in engagement with the teeth of the hub by a spring 13. Therefore, the clutch will be normally held in engagement with the hub extension but may be disengaged therefrom by pressing upon the handle of the cam 14.

A pan or trough 15 is bolted or otherwise firmly fixed upon the top 1 of the frame and centrally of its bottom is formed with a bearing 16 through which extends a spindle 17 having a friction disk 18 at its lower end contacting with the drive gear 8 and at its upper end being fixed centrally of a turntable 19. This turntable constitutes a polishing surface and may be formed of abrading material or of wood or metal and covered with emery cloth or any other desired polishing medium. Posts 20 are disposed vertically in spaced relation to each other circumferentially of the annular wall of the pan and are bored to receive shafts 21 which project downwardly through the table top and are yieldably held against rotation by springs 22 coiled about their extended lower por tions and anchored to the shafts and table top. Arms 23 extend radially of the pan above the turntable or disk 19 and have their outer ends formed with heads 24 fitted upon and pinned to the upper ends of the shafts 21 so that the arms may have swinging movement over the turntable 19 but at the same time be yieldably held against movement towards the periphery of the same. Gears 25 are fixed upon shafts 26 journaled through bearings 27 at the inner ends of the arms 23 and these gears have operative engagement with a drive gear 28 fixed upon a spindle 29. The gears may be friction gears as shown in Fig. 1, or have intermeshing teeth as shown in Fig. 2. It should be noted that the gear 28 is of eccentric formation, as shown in Figure 2, so that it not only 1'0- tates the gears 25 and shafts 26 but also acts as a cam and causes the arms 23 to swing radially of the disk 19 against the action of the springs 22. The spindle or shaft 29 is journaled in a bearing 30 at one end of a supporting arm or bar 31 and at its upper end the spindle carries a beveled gear 32 meshing with a similar gear 33 upon one end of a shaft 34. This shaft 34 is rotatably mounted in bearings 35 extending upwardly from the bar 31 and has one end portion 36 formed as a separate element and adapted to be united to the main section of the shaft by a clutch 3'7 keyed to the main section and movable into and out of engagement with a companion clutch element 38 at the inner end of the auxiliary shaft section 36. The auxiliary shaft section carries a gear 39 at its outer end meshing with a gear 40 upon the upper end of a shaft 41 journaled through a pillar 42 rising from the table top 1 and the shaft 41 also extends through one end of the bar 31 and the corresponding bar 43 of another polishing unit. This bar 43 carries a shaft 44 corresponding to the shaft 34 and carrying a gear 45 meshing with the gear 40 and it will thus be seen that more than one shaft may be driven from the shaft 41. A gear 46 fixed upon the drive shaft 5 meshes with a gear 47 at the lower end of a gear reducer 48 into which the lower end of the shaft 41 extends. Therefore, rotary motion may be transmitted from the shaft 5 to the shaft 41 at a reduced speed. By this arrangement the disk 19 and the hollow shafts 26 will all be rotated and the shafts 26 at the same time caused to move back and forth across the disk radially thereof but the disk rotates at a very much higher rate of speed than the shafts 26.

Referring to Figure 3, it will be seen that at their lower ends the shafts 26 each carries a base or disk 49 from which extend arms or strips 50 and through the shaft extends a stem 51 bored axially to receive a pin 52 of greater length than the stem and projecting from the upper and lower ends thereof. A cup or specimen holding ring 53 is engaged between the arms 50 of each disk 49 and held against rotation between the same by pins 53 extending from the holder and engaging the arms and each ring carries a specimen 54 embedded in cement, plaster or a similar substance 55. A collar 56 is formed about the lower end of each ring to provide a good support and prevent the ring from tilting easily when the machine is in use. The speed at which the disk 19 rotates is liable to cause the cups to tilt and in order to prevent this each cup is engaged at one side by fingers 57 extending downwardly from a plate or side arm 58 projecting from the lower end of the cooperating stem 51, and in order to press the fingers into engagement with the cup there has been provided a leaf spring 59 which bears against the upper end of the stem'about a squared portion 51. An abutment 69 extends from opposite sides of the pin 52 and is engaged by forks at the ends of a leaf spring 62 so that the pin will be pressed downwardly against the center of the cement backing for the specimen and the lower face of the specimen held firmly against the rotating disk 19. The spring strips 59 and 62 are fixed in spaced relation to each other upon a post 63 rising from the arm 23 and from this post extends a side extension 64 carrying a threaded stem 65 which projects upwardly through the spring strips and carries nuts 65 and 66. These nuts bear against the spring strips and by adjusting them the tension of the strips and their pressure upon the spindles 51 and pins 52 may be controlled.

When this machine is in use, specimens to be polished are set into cement poured into the rings or cups 53 and the cups engaged between the fingers 50 of the disks 49. The motor '7 is started to rotate the drive shaft 5 and from this shaft rotary motion is transmitted to the turntable and shaft 29. The gear 23 rotates with the shaft 29 and due to its shape shifts the arms 23 radially of the turntable while imparting rotary motion to the shafts 26 of the carriers. This causes the specimens to be rotated independently of the turntable and shifted radially thereof while being acted upon by the emery cloth or other polishing medium upon the turntable and prevents scratches from being formed upon their under surfaces. Therefore, they will be highly polished and fiaws will show clearly when examined under a microscope or microscopic photographs of the specimens are inspected. It is preferred to have the machine built in sets of three units, the turntable of one unit being covered with coarse emery, the second having its turntable covered with medium fine emery, and the turntable of the third unit being covered with very fine emery. Therefore, the specimen holders may be transferred from the carriers of one unit to another and the specimens first acted upon by coarse emery, then by a medium grade, and finally by fine emery and a very high polish imparted to the faces of the specimens. It will be understood that the number of units may be varied.

Having thus described the invention, I claim:

1. In a polishing machine, a rotary abrading disk, a shaft disposed axially of said disk, a cam gear fixed upon said shaft, arms pivotally mounted and extending over said disk towards said shaft, carriers beneath the free 'mner end portions of said arms having shanks extending up wardly and rotatably carried by said arms, gears upon said shanks meshing with the gear of said shaft whereby the carriers will be rotated and shifted radially of the disk as the cam gear rotates, means to yieldably resist swinging movement of the arms away from said shaft and retain gears carried by said shanks in engagement with the gear carried by the shaft, a drive shaft, means to transmit rotary motion from said drive shaft to the gear carrying shaft, and means to transmit rotation to said disk.

2. In a polishing machine, a rotary abrading disk, a shaft disposed axially of said disk, a cam gear fixed upon said shaft, arms pivotally mounted and extending over said disk towards said shaft, carriers beneath the free inner end portionsof said arms having shanks extending upwardly and rotatably carried by said arms, gears upon said shanks meshing with the gear of said shaft whereby the carriers will be rotated and shifted radially of the disk as the cam gear roposed axially thereof, a cam gear fixed upon said shaft, arms pivotally mounted and extending over said disk towards said shaft, carriers beneath the free inner end portions of said arms having shanks extending upwardly and rotatably carried by said arms, gears upon said shanks meshing with the gear of said shaft whereby the carriers will be rotated and shifted radially or" the disk as the cam gear rotates, means to yieldably resist swinging movement of the arms away from said shaft and retain gears carried by said shanks in engagement with the gear carried by i the shaft, specimen holders engageable with said carriers, a spindle loosely engaged through a bore formed axially through each shank and projecting from the upper and lower ends thereof, a head at the lower end of each spindle to bear against a specimen holder adjacent its periphery, a stem slidable axially through each spindle and projecting above and below the same and resting upon a specimen holder centrally thereof, spring strips carried by said arms and engaging the upper ends of the spindles and stems to press the same downwardly and apply pressure tothe specimen holders, a drive shaft, means to transmit rotary motion from the drive shaft to the gear carrying shaft, and means to transmit rotary motion from said drive shaft to said disk.

4. In a polishing machine, a frame, a pan mounted upon said frame, a bearing centrally of said pan, a shaft extending vertically through said bearing and rotatable therein, a polishing disk at the upper end of said shaft, a friction disk at the lower end of said shaft, posts spaced from each other about the walls of said pan, rocker shafts journaled through said posts and yieldably held against rotation in one direction, arms carried by said rocker shafts and extending over the pan and polishing disk, carriers below the inner ends of said arms having shanks extending upwardly and journaled through the arms, gears upon the upper portions of said shanks, a pillar rising from said frame, a bar carried thereby and projecting over said polishing disk above said arms, a spindle journaled through the inner end of said bar axially of said polishing disk, a cam gear carried by said spindle and meshing with the gears of said shanks to rotate the carriers and shift the same radially of said polishing disk, a shaft journaled through said pillar and having a gear reducer at its lower end,

a shaft carried by said bar for transmitting rotary motion from the last-mentioned shaft to said spindle, specimen holders adapted to be engaged with said carriers and rotated therewith, means to apply downward pressure against said holders and press specimens carried thereby against said polishing disk, a drive shaft rotatably carried by said frame, means to transmit rotary motion from said drive shaft to said gear reducer, and means for transmitting rotary motion from said drive shaft to said friction disk.

5. In a polishing machine, a rotary disk, a shaft rotatably mounted and disposed in axial alignment with said disk, a cam carried by said shaft, arms pivotally mounted and extending tangen-' tially of the disk and yieldably held against swinging movement away from said shaft, carriers having shanks rotatably carried by said arms, power take off elements carried by said shanks and engaging said cam whereby the cam serves to rotate the shanks and impart swinging movement to the arms and carriers radially of the disk, and means to rotate the disk and shaft.

6. In a polishing machine, a rotary disk, arms pivotally mounted and extending across the disk at tangents thereto and yieldably held against movement towards the periphery of the disk, carriers rotatably connected with said arms and having movement radially of the disk when the arms are moved, a cam rotatably mounted with its axis in axial alignment with the disk, means actuated from said cam to transmit rotary motion to the carriers and swinging movement to the arms as the cam rotates, and means to impart rotary motion to the cam and disk permitting rotation of the disk at a regulated rate of speed.

'7. In a polishing machine, a rotary abrading disk, an arm pivotally mounted for swinging movement across said disk transversely of the direction in which the disk rotates, an article carrier rotatably connected with said arm and having a gear concentric therewith, an eccentric cam gear rotatably mounted with its axis axially of said disk, said cam gear engaging the gear of said holder to impart swinging movement to the arm 12 and rotary motion to the holder as the cam rotates, the arm being yieldably held against swinging away from the cam gear, and means to impart rotation to the disk and cam. 

